Physical Science 17.4

Multiple Choice

The intensity of sound waves is measured in units of

• hertz (Hz)

• decibels (dB)

• joules (J)

• meters (m)

Multiple Choice

Most musical instruments vary pitch by

• changing the amplitude of sound waves

• reflecting sound from surfaces in a room

• changing the frequency of a standing wave

• using the Doppler effect

Multiple Choice

The Doppler effect is

• a change in sound frequency caused by motion of the sound source relative to the listener

• used in a variety of applications including sonar and ultrasound imaging

• a technique for determining the distance to an object under water

• the rate at which a wave’s energy flows through a given area

Multiple Choice

What part of the human ear acts as an amplifier to increase the motion of the eardrum?

• ear canal

• middle ear

• inner ear

• auditory nerve